Access node and method

ABSTRACT

An all-encompassing fully integrated communication Access Node for call stations and other security and communications equipment includes a modular housing within which is mounted wire and wireless communication systems and power systems. The housing has a chassis for mounting the electronics and battery modules and a backbox and panel for staged installations, managing cables and providing heat dissipation. A door to the chassis is secured using latch hooks with roller bearings. Optical cable termination is provided as a two sided patch panel. Dual power supplies provide power to internal components and to external components via a distribution module. Backup power is provided by a custom battery backup with a charging controller. Cooling is controlled by dual fans and a fan controller moving air through the housing using openings and baffles. Freestanding pedestal mounting of the Access Node and various other mounts for column, wall, or ceiling to any substrate or condition is an option. Venting through a plug prevents pressure build up.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional patent application of co-pending U.S.patent application Ser. No. 14/968,761, filed Dec. 14, 2015, which isincorporated herein by reference. This application is a divisionalnon-provisional application that claims the benefit through co-pendingU.S. patent application Ser. No. 14/968,761 of U.S. Provisional PatentApplication Ser. No. 62/091,196, filed Dec. 12, 2014, which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to a communication device orAccess Node for a public communication system and more particularly to acommunication Access Node for use in a public transportation facility orother location.

Description of the Related Art

People in public transportation facilities, such as train stations,subway stations, and bus stations, may need assistance or information.For example, people in public transportation facilities may needassistance if they become a victim of a crime or if they feel threatenedwith a possible crime. People in the public transportation facility mayneed information, such as time to next train, subway or bus arrival,time of last train for the evening, directions, etc. To address thisneed, operators of public transportation facilities are providing callstations at locations within facilities. Commonly, several call stationsare provided within a transportation facility. The call stationsgenerally include a call button for indicating an emergency and mayinclude an information request button for requesting information.

The call stations may be connected through communication equipmentmounted in a column, wall, and ceiling or otherwise near the callstations to provide communication to a communication center or toprovide contact to an emergency service or information source. Thecommunication equipment may communicate with a plurality of the callstations or other security devices. For example, the communicationequipment may communicate with all of the call stations within a subwaystation, for example, linking the call stations to the communicationcenter.

Call stations may be provided at other locations as well. For example,call stations may be provided on college campuses, in parking garages orparking lots, at tourist attractions, or in any location where desired.

SUMMARY OF THE INVENTION

A communication device, also referred to as an Access Node, provides asingle housing for communication equipment that links a plurality ofcall stations and other security based equipment to a communicationcenter or other communication destination. The housing may enclose wiredand wireless network communication devices, a power supply, a backuppower supply, cable connectors and patch panels, a cooling system,sensors, and/or other equipment. The housing is easily mounted to avariety of mounting surfaces at a location that permits ready access forservicing and upgrades. The housing provides a NEMA 4 sealed and secureenclosure for the communication equipment. The housing is durable andreduces the chance of unauthorized access to the enclosed equipment.

The Access Node has a modular construction so that it may be configuredto meet the demands of each installation. The installation of a singleAccess Node provides all of the necessary equipment needed forcommunication with a plurality of call stations and security devices.The equipment within the housing is readily accessible by servicepersonnel for ease of servicing and upgrading. The Access Node includesthe equipment within the housing which may be configured as needed toaccommodate various data and power needs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a communication device or AccessNode according to an embodiment of the invention;

FIG. 2 is a functional block diagram of an embodiment of thecommunication device or Access Node;

FIG. 3 is a front perspective view of an embodiment of the Access Nodemounted on a pedestal mount;

FIG. 4 is a front perspective view of an embodiment of an upper frame ofthe pedestal mount;

FIG. 5 is an exploded view of an embodiment of a lower portion of thepedestal mount;

FIG. 6 is a front perspective view of an optical cable terminator patchpanel as may be used in the Access Node;

FIG. 7 is an enlarged perspective view of a latch hook as may be used inthe Access Node;

FIG. 8 is a front view of the Access Node with the door in an openposition;

FIG. 9 is a perspective view of back panel for the Access Node of FIG.8;

FIG. 10 is a perspective view of a redundant power supply for the AccessNode;

FIG. 11 is a wiring circuit diagram of the redundant power supply;

FIG. 12 is a perspective view of a battery backup for the Access Node;

FIG. 13 is an exploded view of the battery backup of FIG. 12;

FIG. 14 is a graph showing the charging of the battery backup;

FIG. 15 is a functional block diagram showing a battery pack with safetycircuits;

FIG. 16 is a perspective view of an Access Node with a plurality of callstations ready for installation;

FIG. 17 is a perspective view of an auxiliary DC power distributionmodule for the Access Node;

FIG. 18 is a schematic diagram showing a cross section of the AccessNode and indicating air flow for cooling;

FIG. 19 is a perspective view of a portion of the Access Node showing avented plug;

FIG. 20 is an exploded isometric view of an alternative embodiment ofthe latch hook;

FIG. 21 is a fragmentary cross sectional view showing the latch hook inan unlatched position;

FIG. 22 is a fragmentary cross sectional view showing the latch hook ina partially latched position;

FIG. 23 is a fragmentary cross sectional view showing the latch hook ina fully latched position;

FIG. 24A is a cross-sectional view of the access node showing the doorin a first position during opening and closing of door 14 on the housing12 and FIG. 24E is an enlarged view of the hinge in the first position;

FIG. 24B is a cross-sectional view of the access node showing the doorin a second position during opening and closing of door 14 on thehousing 12 and FIG. 24F is an enlarged view of the hinge in the secondposition;

FIG. 24C is a cross-sectional view of the access node showing the doorin a third position during opening and closing of door 14 on the housing12 and FIG. 24G is an enlarged view of the hinge in the third position;

FIG. 24D is a cross-sectional view of the access node showing the doorin a fourth or closed position during opening and closing of door 14 onthe housing 12 and FIG. 24H is an enlarged view of the hinge in thefourth or closed position; and

FIG. 24I is an enlarged cross-sectional view of a portion of FIG. 24Dshowing a gasket construction in the fourth or closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a communication device or Access Node 10. The Access Node10 provides a single housing for communication equipment that links aplurality of call stations and other security based equipment to acommunication center or other communication destination in a publictransportation facility or other location. The single enclosure providesease of installation and maintenance for the network communicationequipment. The Access Node provides the network communicationsinfrastructure for call stations as well as other Ethernet safety andsecurity communications equipment like cameras, air purity detectors,proximity detectors, RF identification and other wireless applicationsdesigned to track individuals. The 100 meter distance limitation ofEthernet often prevents the distribution of such devices within aTransit environment. The Access Node, being fiber fed provides basicallydistance limitless optical transmission at very high digital speeds to acore network. The Access Node 10 includes a housing 12 and a door 14.The housing 12 and the door 14 enclose an interior space 16 when thedoor 14 is closed. When the door 14 is closed and locked, access to theinterior space 16 is generally prevented except by authorized persons.Within the interior space 16 is provided mounting structures formounting equipment including network and communications equipment asneeded. Depending on the needs of a particular installation, theinterior space 16 may be provided with wired and wireless network switchdevices, PC based application server and drive storage arrays, powersupplies, connectors and patch panels, cooling fans and thermalmanagement systems, power distribution and regulation, cable mountingand routing, backup power supply, intrusion protection and detection,temperature and humidity monitoring, structures for mounting to variousmounting surfaces; and other features. The housing 12 may be thought ofas a hotel in which equipment and systems needed for each installationcan be located.

The housing 12 and door 14 together form an enclosure having a generallycolumnar shape. The enclosure of certain embodiments has no visibleexternal fasteners when in a closed and locked position. Vandalism andtheft are thereby discouraged. The columnar housing 12 is similar inshape and size to call stations that may be provided in many publictransportation facilities, and may be provided with similar aestheticfeatures as the call stations.

As shown in detail in FIG. 24, the door 14 is connected to the housing12 by a concealed hinge assembly 18 that is configured to be entirelyenclosed within the housing when the door is in the closed position. Thehinge assembly 18 provides two-motion operation, first pivoting toward aclosed position and then moving in a translational motion as a secondmotion to engage the door 14 against the housing 12. The hinge 18comprises a rotating hinge 18A and a stationary hinge 18B. Thestationary hinge 18B has a stationary pin 18BA and a slot 18BB. Therotating hinge 18A has a pin 18AA and a slot 18AB. The slot 18AB of therotating hinge 18A is constrained to the stationary pin 18BA of thestationary hinge 18 b. The rotating hinge's pin 18AA is constrained tothe slot 18BB of the stationary hinge 18B and travels in a linearportion of the slot 18BB of the stationary hinge 18B upon closing thedoor 14. By constraining the rotating hinge's pin 18AA to the linearportion of the slot 18BB on the stationary hinge 18B, along withconstraining the slot 18AB of the rotating hinge 18A to the fixed orstationary pin 18BA of the stationary hinge 18B, an arching motion thatis smooth and controlled, and a sealing results on the hinged side ofthe door and enclosure. In addition to sealing the hinged side of theenclosure, the door cannot be slammed shut, unlike doors with typicalhinges containing a single pivot point. This ensures that the door 14 isfully sealed against the housing 12. The two-motion operation of thedoor 14 during opening operation permits the door to move to its openposition out of the way when access to the interior is required. Fourhinge assemblies 18 are provided in the illustrated embodiment. A gasket20 or other liquid tight seal is provided between the door 14 and thehousing 12. In certain examples, the gasket 20 is mounted on the door 14in a position so that it is compressed between the door 14 and housing12 following the second motion of the hinge 18. The door 14 and gasket20 are also shown in FIG. 24 with the door in the open and closedposition where the full sealing is provided for. In FIG. 2 the gasket 20detail is shown. With the last 10° of rotation, the face of the door isforced by the dual action of the hinge towards the chassis to form awater tight seal. In the gasket detail the chassis 400 is shown, thedoor 14 is shown, a mortise 401 is shown, and a tenon at 402 is shown. Alip on a perimeter of the enclosure creates two continuous sealingpoints between gasket and enclosure. The gasket detail in step 4 showsthe gasket compressed and sealed in the closed position.

The housing 12 may be locked and/or unlocked by an electronic programmedkey that fits into a key hole 22 at a lower end of the housing 12. Theelectronic key permits opening of the door only by a key that includes apredetermined encrypted key code that binds the key to that device. Theaccess by the electronic key is logged in an access logging system inthe Access Node 10 to provide an audit trail of accesses and/or accessattempts to the housing 12. Once the electronic lock is unlocked, alatch handle 24 may be pivoted to an open position as shown. When thehandle 24 is in a closed position, the handle is located within a recessin the underside of the housing 12. As the latch handle 24 is movedbetween the open and closed positions, the handle movement moves aslider bar within the housing 12 to latch and unlatch the door locks.More information on the door locks will be provided hereinafter.

The housing 12 is of a modular construction to permit modification ofthe housing and the interior space 16 to meet the needs of eachinstallation and to permit servicing and upgrading of the Access Node104 to add or remove call stations, or to permit upgrading or replacingof equipment. The fasteners used to mount the equipment and to assemblethe modular components are all of a same type so that a service personmay use a single tool to remove and replace each of the modularcomponents within the housing. In one example, a number 1 Phillipsscrewdriver may be used to remove and install all of the componentswithin the housing.

In the illustrated example, the housing 12 is formed of a front chassis26 and a rear panel or back box 28, which will be described in moredetail. The housing 12 has been equipped with the following features andequipment for an example of an installation, a solid end cap 30, anenvironmental sensor 32, an auxiliary power distribution module 34, acable patch panel 36, a first Ethernet switch 38 (or an applicationserver/embedded PC), a second Ethernet switch 40, a battery pack 42(which may preferably comprise an AGM battery, a lithium battery, orother suitable battery), a UPS (uninterruptable power supply) module 44(a first swapable charging personality module), a power module 46, aconvenience electrical outlet 48, a fan module 50, and a bottom end cap52. On the door 14 is provided a wireless radio access point module 54that is connected to the housing by a cable 56 that extends from thehousing 12 to the door 14 near the topmost hinge 18 in thisillustration. The modular components can be installed, removed orreplaced as needed. Also on the door 14 are provided four pockets 58that are engaged by latch hooks, as will be described.

The housing 12 is constructed so that it may be mounted using numerousmounting options. The housing 12 may be mounted to columns including toround, square or other shapes of columns, on or within the recesses ofI-beam columns, on walls, fences, grates, or other mounting locations.In certain embodiments, a free standing pedestal mount is provided, aswill be described. The housing 12 may be mounted and operated either ina vertical orientation as shown or in a horizontal configuration. In theillustrated embodiment, the rear panel 28 is provided with expandablecolumn gripper assemblies 60 for mounting the Access Node 10 within arecess of an I-beam, for example. Embedded and threaded conduit threadedconnectors are provided on the top and bottom of the rear panel 28 forexternal connection of wires and cables.

The modular construction of the Access Node 10 permits a phased-ininstallation of the device. The Access Node 10 and one or a few callstations may be installed in a location at first. As call stations areadded, communications and network equipment may be added and upgraded inthe Access Node 10 to accommodate the growth. Phased installation ispossible without requiring that the Access Node 10 be replaced with adifferent Access Node at each phase to add capacity, for example. It isalso not necessary that an Access Node 10 be provided with all theequipment that it will ultimately be need for an installation site, evenif that equipment will not yet be used in the initial installation,since the Access Node may be readily upgraded in the future.

In the an example, the Access Node is provided with a 500 watt powersupply, NEMA 4 designed chassis and input/output connectors, anelectronically controlled access lock, Ethernet managed and hardenedswitch, integrated wireless licensed and unlicensed MESH tri radioaccess point, 2.4 GHz quad core Pentium processor server with 4 TB harddisk storage, AC power distribution with indication and main circuitprotection, DC power generation and distribution with indication andcircuit protection, integrated UPS power control module and lithium ionbattery pack, a multipoint door latching system, an 8-point ST, 16-portLC or 8 port SC fiber distribution panel, a fiber management andclamping system, a quick connect AC power system, an internal AC linefiltering and transient protection system, AC utility convenienceoutlet, dual PWM fans with thermal feedback speed control, andintrusion, temperature, humidity, dew, and fan detection. SNMP (systemnetwork management protocol) monitoring is provided.

In an example, the housing 12 has a chassis 26 with dimensions of 64.12inches by 7.5 inches by 4 inches, not including an antenna radome. Aback box or rear panel 28 has dimensions of 64.12 inches by 7.5 inchesby 1.75 inches. The operating voltage is 90 to 264 VAC, autoranginginput. The operating power consumption is a maximum of ˜100 watts forinternal components. Maximum power consumption PoE (power over Ethernet)is 310 watts under full load while running 16 ports on 802.3af. Theswitching power capacity of the exemplary unit is 16 ports. 802.3at PoEis possible and limited by firmware to the maximum available powerdelivered by the power system. It is envisioned that one port is usedfor environmental purposes, one port is used for the UPS, and one isused for the access point. The wireless operation complies with FCCstandards.

An example Access Node is constructed to operate in environments rangingfrom −20 to +60 degrees C. The device is configured to operate at up to95% humidity, non-condensing. The chassis weight has a weight ofapproximately 70 pounds, depending on the configuration.

The housing 12 and door 14 may be of extruded and then machined metal toprovide a rugged chassis and enclosure. The housing 12 and door 14 areconstructed to withstand the harsh and unpredictable environment ofpublic transportation facilities. The materials used include anodizedaluminum, powder coated aluminum, stainless steel, Poron, neoprene,silicone, stainless steel, fiberglass and UHMW-PE.

FIG. 2 is a block diagram of the Access Node 10 as shown in a one-linediagram 62. At the upper left is provided a rear junction box andconduit entry block 64. The entry block 64 carries two 12 FOC (fiberoptic cable) lines 66 and 68, a 120 VAC line 70, and a CAT 6 Ethernetline 72. The 12 FOC lines are marked as FOC east 68 and FOC west 66 andconnect to an FDP (fiber distribution panel) block 74 that is indicatedas FOC patch chords. The FDP block 74 connects to a first Ethernetswitch 76 and a second Ethernet switch 78. The switches 76 and 78connect to a wireless access point block 80, here a tri-radio (MotorolaAP7161) wireless access point. The switches 76 and 78 have an outputEthernet line 82 connected to a RJ45 coupler 84 (which is optional).Another output line 86 is an Ethernet with POE (power of Ethernet) thatconnects to an environmental monitoring sensor (EMS) device 15 block 88.

Block 88 includes an environmental monitoring system. In certainembodiments, the EMS device 88 detects opening of the door and anycabinet intrusion. It also monitors temperature and humidity sensors,monitors the fan operation, and monitors the power supply condition. TheEMS device 88 reports the monitored conditions via SNMP to an Ethernetswitch.

The EMS device block 88 connects to a first Analog to Digital (A-D)block 90 that is connected to a door switch 92. The A-D block 90includes an analog to digital bridge converter for analog to digitalconversion and EMF blocking. The EMS device block 88 also connects to asecond A-D 94 that in turn is connected to a fan controller 96. The fancontroller 96 connects to a first fan 98 and second fan 100. The fancontroller 96 controls the fans 98 and 100 depending on a signal from athermistor 102. The fan controller 96 is supplied with power from a DCdistributor 104, which here is a 48 volt DC distributor, via line CB1,part number 106.

The voltage distributor 104 also provides power to the switches orapplication server 76 and 78 via line CB2, part number 108. The voltagedistributor 104 has a 48 volt DC line that is connected to a UPScontroller 110 that in turn is connected to a battery pack 112. Thevoltage distributor 104 receives its power from an AC to DC converter114 that includes a 250 watt rectifier. The converter 114 may optionallyinclude a redundant 250 watt rectifier or converter 116, as indicated inbroken lines. The rectifier or converter 114 receives it power from a110 volt AC distribution, line filter and pilot block 118. The ACdistributor 118 has one output, labeled CB1, connected to a 110 voltutility output 120, a second output CB2 to the converter 114 and a thirdoutput CB3 optionally connected to the redundant converter 116. Theinput of the AC distributor 118 has an input connected to line 70through the rear junction box 64 via which it receives the 120 volt ACpower. The remaining line 72 through the junction box includes up to 15CAT 6 patch cords that are fed by the Ethernet switches 76 or 78.

In FIG. 3 is shown a pedestal mounted Access Node 10. A pedestal 122 maybe mounted on a floor or platform surface and may be freestandingwithout the need to be mounted to a column, wall, ceiling, grate, fenceor other vertical surface. The pedestal 122 has a base plate 124 fromwhich extend a vertical plate 126. Two gussets 128 provide reinforcingsupport between the vertical plate 126 and the Access Node housing 12.The door 14 of the Access Node 10 is shown in the open condition. Incertain embodiments, the vertical plate 126 forms the rear panel or backbox 28 of the Access Node 10. In particular, a different rear panel orback box 28 may be provided for a pedestal mounted Access Node 10 thanfor a wall or column mounted Access Node. The back box 28 may bespecific to the mounting location and configured as need. In theillustration, the back box 28 goes to the base of the pedestal mount.Wall or column mounted Access Nodes may use shorter back boxes.

FIG. 4 shows components of the pedestal 122. Two vertical beams 130 and132 are connected by an upper linking support 134. Forward extendingmounting projections 136 and pedestal gussets 138 are provided on thebeams 130 and 132 on which the rear panel 26 may be mounted. A shelfportion 140 is provided between the beams 130 and 132 and the lowergussets 128.

FIG. 5 shows the components of the pedestal 122 according to a certainembodiment. The pedestal includes the upper linking support 134connecting the vertical beams 130 and 132. The beams 130 and 132 areintegrally formed with the projections 136, pedestal gussets 138 and thegussets 128. The base 124 includes a lower base member 142 that may befastened to floor or platform and an upper base member 144 that isfastened to the lower base member 142. Hooks 146 on the lower end of thebeams 130 and 132 engage into the upper base member 144 and are securedby the shelf portion 140. Various screws bolts, nuts, and washers 148are provided to hold the parts together.

FIG. 6 shows the front chassis 26 from which the rear panel or back box28 has been removed. The solid end cap 30 is provided at the end of thechassis 26. A portion of the wireless access module 54 mounted on thedoor 14 is visible in the open position with a single hinge 18 in thisview. Within the chassis 26 is mounted the environmental sensor 32 andthe power distribution module 34. The chassis 26 includes a perforatewall 148 within the chassis 26 on which may be mounted variousequipment. The perforate wall 148 includes openings 150 through whichmay be passed cables and wires and through which may flow air forcooling of the equipment in the Access Node 10.

The chassis 26 of the illustrated embodiment includes a fiber opticcable (FOC) management system 152. The cable management system 152 ismodular and may be configured for the capacity needed and may beupgraded as additional capacity is needed. In the illustration, fourangle members 154 are each connected to the perforate wall 148 by a hook156 that is inserted into a slot 158 in the perforate wall 148 and slidparallel to the wall 148 to engage the hook 156 in the slot 158. Eachangle member 154 is secured by a screw 160 through the angle member 154and into the perforate wall 148. As few or as many angle members asneeded may be installed.

To each installed angle member 154 may be attached a low profile duplexLC patch panel 160. Each patch panel 160 has a lower tab 162 that isinserted into a slot 164 in the perforate wall 148. A screw 166 isfastened through the patch panel 160 and into the corresponding anglemember 154. As few or as many patch panels 160 may be installed asneeded. Each of the patch panels 160 includes two duplex fiberterminators 168. One duplex fiber terminator 168 is provided on eachside of each patch panel 160. In the illustrated embodiment, up tosixteen optical fiber cables may be connected to the patch panels 160 atthe sixteen fiber terminators of the low profile panel.

Fiber breakouts provide openings 150 through the chassis 26 to permitrouting of the cables and wires on the back side of the chassis and tothe terminators 168 on the front side of the chassis 26. Cable andVelcro strips are provided to permit organizing of the fiber tails.

Also visible in FIG. 6 are portions of the door latching mechanism. Inparticular, along a side of the housing 12 is a sliding strip 170. Thesliding strip 170 moves as the handle 24 at the bottom of the housing ismoved. The sliding strip 170 is held in place by a fastener 172 thatextends through a slot 174 in the strip 170 and into the housing 12. Theslot 174 permits longitudinal movement of the strip 170. On the strip170 is mounted a plurality of latch hooks 176, one of which is shown inthis figure. The latch hook 176 is mounted so as to be adjustable toaccommodate variations in the housing 12 and door 14 to thereby insurethat the door is secured in a closed and sealed position. The latch hook176 is shaped to engage a corresponding pocket 58 on the door 14. Thelatch hook 176 is mounted on two threaded studs 178 that extend from thesliding strip 170 in a direction parallel to the closed door 14.

Turning to FIG. 7, the latch hook 176 is a machined block of material,such as metal, that is configured to secure the door 14 in a closed andlocked position on the housing 12. The latch hook 176 has two openings180 that fit onto the screw studs 178 on the sliding strip 170. Thelatch hook 176 is adjusted on the screws studs 178 by set screws 182 toadjust the angle of engagement so as to therefore affect the amount ofvertical influence on the door and finally the seal. The mounting screwstuds 178 may be kept loose when first fastening the door closed so thatthe latch hooks can be adjusted by the setscrews by inserting a toolfrom behind the Access Node chassis using specially located accessports. Once the latch hook 176 moves into a position on screw studs 178then the screw studs 178 are tightened final torque to engage thecorresponding pocket 58. The set screws 182 have then ‘jacked’ and thescrew studs may then be tightened to hold the latch hook 176 in thefinal adjusted position.

The latch hook 176 defines a channel 184 into which a wall of the pocket58 fits when the latch is engaged. The channel 184 forms a hook portion186 that fits into the pocket 58 during engagement. The channel 184 istapered from a wider opening to a narrower throat so that the pocket 58is engaged more securely as the latch hook moves to the fully engagedposition. The wall of the pocket 58 encompasses bearings that bearagainst the throat of the channel 184 in the fully engaged position. Toassist in initial engagement of the latch hook 176 on the pocket 58, theend 188 of the hook portion 186 is provided with a roller bearing 190mounted on a pin 192. As the door latch is being engaged, if the end 188of any of the latch hooks 176 strike the pockets 58, the roller bearing190 permits the end 188 to move on the pocket 58 so that the latch hooks176 move into the engaged position. The pockets 58 may be U-shapedmember projecting from the inside surface of the door 14 and shaped sothat the hook portion 186 may fit into the pocket 58.

As the latch handle 24 is pivoted to the closed position, the slidingstrip 170 slides in the housing 12 and the latch hooks 176 are eachmoved into a latching position with the pockets 58 on the door 14. Inthe illustrated example, four latch hooks 176 engage four pockets 58that are spaced along the length of the door 14 so that the door 14 isheld in a closed and sealed position.

The leading edge of the door assembly is equipped with the latch pockets58. The latch pockets 58 are set into a milled boundary of the door 14to ensure that they are properly indexed by jacking setscrews andsecured with two screws. Once the door 14 is shut, the latch pockets 58interact with the latches 176. The roller bearing 19 grabs the pocket 58as the chassis latch handle 24 at the bottom of the housing 12 is movedto a lock position. As the latch 176 engages within the pocket 58 it isforced tight by the taper inside the slot 184. Upon full extension ofthe latch handle 24, the pocket 58 bears with full pressure on thethroat of the latch 176. This alleviates undue pressure on the tip ofthe roller bearing 190. The latches 176 attach to the slider strip 170that interconnects to the Access Node lower handle 24. The latch 176 isadjustable to accommodate imperfections that that might be present inthe chassis 26. The action draws a tenon rib milled around thecircumference of the chassis into a mortise grooved around thecircumference into the door, with a neoprene gasket between them, thuscreating a watertight seal.

An alternative embodiment of the latch hook is shown in FIG. 20.

FIGS. 8 and 9 show the chassis 26 separated from the rear panel or backbox 28. The controls and connectors and other maintenance and repairstructures are mounted for access at the front of the chassis 26 via thedoor 14, generally on the forward side of the perforate wall 148. Thelatch hooks 176 may be seen along the left side of the front opening,and the pocket 58 may be seen at corresponding positions on the door 14.Wiring, cabling and the like extends behind the perforate wall 148 in aspace between the perforate wall 148 of the chassis 26 and the back boxor rear panel 28. The perforate wall 148 may be provided with mountingbrackets 194 on which are mounted the network switches 38 and 40. Othermounting brackets for other equipment may be provided on the perforatewall 148 or elsewhere within the housing 12.

The back box or rear panel 28 is shown in FIG. 9. The rear panel 28 maybe fastened to the chassis 26 to enclose the back of the chassis 26. Therear panel 28 has a top end cap 196 that includes a conduit entry bywhich cabling may be brought into the Access Node 10. Keyhole openings198 are provided at four positions in the rear panel 28 to engage withmating male studs for temporarily hanging the unit prior to mounting therear panel, as an installation convenience, to the chassis 26.Ultimately, eight shoulder type screws are used to draw the frontchassis to the rear, with gasket between, for a watertight seal. Fiberoptic cable clamps 200 are provided on the rear panel 28 for holdingoptical cable that may be terminated at the patch panel 160 in thechassis 26. An optional mounting 202 is provided for additional opticalcable clamps. An input power termination 204 is provided adjacent athree pole quick disconnect connector 206. A grounding stud 208 is alsoprovided on the rear panel 28. A bottom end cap 208 of the rear panel 28may be provided with a conduit entry as an option.

The rear panel 28 may be provided with mounting hardware for mountingthe Access Node. Different mounting hardware is provided according torequirements of the installation site. In the illustrated embodiment,the Access Node 10 is to be mounted between the plates of an I-beam orwithin another enclosed space. A pair of column gripper assemblies 210is shown in the illustrated example. The column gripper assemblies 210each include a pair of threaded bolts 212 extending through threadedsleeves 214 in the rear panel 28 and into a turnbuckle 216. Rotation ofthe turnbuckles 216 in a first direction draws both bolts 212 inward sothat the Access Node 10 may be placed in the mounting recess. Rotationof the turnbuckles 216 in an opposite direction moves the bolts 212outward to press on the interior walls of the mounting recess.

FIG. 10 shows the power supply module 46 removed from the Access Node10. The illustrated power supply 46 is a dual power supply having two250 watt power supplies connected as a redundant power supply for atotal of 500 watts of power. The dual power supply 46 uses two 250 wattrectifiers, two 10 amp circuit breakers, two hold up bus capacitors(HUB), and an active OR circuit with alarm reporting. The power supplymodule 46 may supply 500 watts of continuous power or the second powersupply may be used as a hot standby of the 250 watt power supply beingused. The module includes a PI2127 Cool-ORing integrated circuit with ahigh speed ORing MOSFET controller and low on-state resistance MOSFET.The ORing provides extremely low forward voltage drop, which couldinterfere with load sharing, and very low heat generation. The ORingprevents reverse biasing of individual rectifiers when one or both areoff and great potential exists from the battery pack.

The illustrated power supply module 46 includes a front mounting plate218 on which are provided six indicator lamps 220 and six circuitbreaker switches 222 by which a service technician may control power tocomponents of the Access Node. The front plate 218 has the convenienceoutlet 48 by which service personnel may power test or communicationsequipment while working on the Access Node 10. Behind the front plate218 are provided the two power supply rectifiers 224 and 226. Fourelectrolytic capacitors 228, 229, 230 and 231 are provided adjacent tothe front plate 218. The capacitors 288-231 function as hold-upcapacitors for filtering any drop outs from the incoming power. In acertain example, the capacitors are 820 mF capacitors and provide noless than 100 milliseconds of hold up under load. The capacitors 228 and230 are mounted on a rear frame 232 that support the other parts of thedual power supply 46 as a modular unit. An output cable 234 with aconnector 236 extends from the dual power supply 46.

FIG. 11 shows the dual power supply 46 as functional elements. Theconnector 236 connects to ground and to a neutral bus 238 and to two ofthe circuit breaker switches 222. Each circuit breaker switch 222 isprovided with an indicator lamp 220. Two rectifiers 240 and 242 areprovided, each connected to one of the capacitors 228 and 230, shownhere as hold up capacitors. The active ORing function is provided aselement 244 connected to both rectifiers 240 and 242. A DC printedcircuit board 246 is provided on which is a ground bar 248, a return 250and a UPS option plug 252. Connectors 254, 256 and 258 are provided forthe Ethernet switches, the environmental sensors, and external power,respectively. The switches 222 are connected to control operation of theEthernet switches or application servers, the EMS device, externalpower, the utility outlet, the first rectifier and the second rectifier.

In FIG. 12, the UPS battery back-up module 42 is shown. The module 42 isprovided within a housing 260 that is designed to pass cooling airthrough it and is configured to fit into the Access Node 10. The housing260 includes a front cover 262 and a cable harness 264 with a four pinbattery pack connector 266. The battery back-up module uses batterycells to create a DC voltage when needed. The battery back-up module isof a form factor to fit into the housing and mount to the chassis. Thehousing 260 is formed of fire retardant ABS. In an example, the batterymodule 260 provides 48 volts DC of power for several hours. The outputvoltage is the result of connecting 14 of the cells in series to yield50.4 volts DC. Two such series connected cells are provided in parallelas parallel battery blocks.

In FIG. 13 is shown an exploded view of the structure of the batteryback-up module 42. It includes a rear cover 268, a rear collectorprinted circuit board 270, and a battery pack ABS chassis 272 formed ofchassis components 272A, B, C, and D provided with through openings tohold battery cells 274 and also designed so that air flows from the topof the unit to the bottom of the unit. Where a solid pack wouldotherwise restrict air, the continuous flow of air through the packallows not only individual cell cooling but also cooling for the entireAccess Node. The chassis 272 has 28 openings in the example. A PCMprinted circuit board 268 is provided at the bottom of the module 42. Afront collector printed circuit board 270 and the front cover 262complete the module 42. The battery cells 274 contact the two circuitboards 268 and 270 to provide power from and to the cells and formonitoring of the battery cells 274. The circuit boards and covers maybe secured to the chassis 272 by screws. A strain relief 282 is providedon battery cable harness 264.

In the graph of FIG. 14, the charging of the battery back-up module 42is shown. The vertical axis is voltage amplitude and the horizontal axisis time. Lithium ion battery cells in the module are provided with aconstant voltage/constant current charging method in which the voltagebetween the charging terminals is maintained at 4.2 volts per cell. Thebattery voltage is shown as line 284 and the battery current is shown asline 286. A prequalification to fast charge transition is shown at 288.A charge current to charge voltage transition is made at 4.1 volts at290. An end of charge current is indicated at 292.

Turning to FIG. 15, a battery pack charging system 294 is shown. Thecharging system includes the battery pack 296 which has a positive input298 that connects to a safety circuit block 300 that includes acontroller IC 302 that connects to two control switches 304 and 306. Thecontrol switch 304 and the controller IC 302 are connected across thebatteries 308 to control charging of the batteries. The control switch306 is connected to a temperature fuse 310 that is in turn connected tothe negative input 312. A thermistor 314 is connected between controlswitch 306 and a T output 316.

The controller IC 302 measures the voltage for each parallel batteryblock (of 14 cells each). The controller IC 302 shuts off a controlswitch to either prevent over charging or to prevent over discharging.The voltage of the control switch is measured on both ends of thebattery block and the control switches shut off the voltage if itexceeds specifications. The control switches 304 and 306 turn off thecharging or discharging depending on the output of the controller IC302. The temperature fuse 310 cuts off the current if abnormal heatingis sensed. The thermistor 314 is provided to measure the batterytemperature within the battery packs. The resistance value of thethermistor 314 is measured between the negative terminal 312 and the Tterminal 316 by the battery or the charger. The charger controls thecharging current until charging is terminated. A noise filter providedat the voltage detectors limits outside noise from resulting in batterymalfunction.

The safety circuit 300 stops the charging per cell when the voltagereaches an upper threshold and resumes charging when the voltage fallsbelow a lower threshold. The safety circuit 300 prevents over dischargeby halting discharge when the battery voltage falls below a lowerdischarge threshold and resumes discharge when the battery voltageexceeds an upper discharge threshold. Discharge is also halted if ashort occurs across the terminals.

FIG. 16 shows an example of the Access Node 10 with the door 14 open andfully equipped to handle multiple call stations. A plurality of callstations 318 are shown adjacent the Access Node 10. The call stations318 may be connected for communication through the Access Node. The callstations 318 and Access Node 10 are mounted in a rack 320 for handlingand delivery to an installation site, such as a subway station. The callstations 318 are mounted at locations throughout the subway station, forexample, and are connected to the Access Node 10 which is mountednearby. A person in the subway station who needs emergency assistance orwho wishes to report an emergency situation may press the emergencybutton 322 on a call station. The emergency information is transferredto the Access Node where vital information such as video can beprocessed and stored. Then the call and information can be engaged to anemergency call center, for example. If the person only seeksnon-emergency information, such as a train schedule or directions, theymay press the information button 324 on a call station 318. Theinformation request is communicated through the Access Node 10 to aninformation center. Two way communications are possible via the callstations 318. Up to 16 call stations may be connected to the Access Node10 in the illustrated embodiment, although other numbers of possibleconnections are within the scope of this invention.

FIG. 17 shows the DC power distribution module 34 that is provided inthe Access Node 10. The power distribution module 34 may be used to feedexternal devices with 48 volts of DC power from the Access Node powersupply module. Four power ports 326 are provided in the illustratedembodiment. Up to 12 ports may be installed in a daisy chain connection.Each port 326 feeds up to 60 watts of power via a polyfuse distribution.An LED indicator light is provided for each port. A 5 amp circuitbreaker and a disconnection switch are provided in the powerdistribution module 34, along with additional filtering and transientsurge suppression circuitry so that clean power is provided to theexternal devices. Any downstream overloads are indicated, withoutimpacting other ports. The polyfuses reset automatically after theovercurrent returns to a permissible range. Class 2 safety concerns aremet and also, any downstream short circuit on any particular branchwon't interfere with other devices that remain in operation.

Thermal management within the enclosed and sealed space of the AccessNode 10 is provided. A fan control module 96 operates the fans andmonitors any failures as well as provides reporting. The EMS device 88monitors internal capabilities and external sensor operation. The frontchassis 26 houses the electronics and the batteries while the rear panel28 provides cable management, heat dissipation, wire management and amounting bracket. The assembled housing 12 provides a cooling tubestructure. The cooling tube is shown in FIG. 18. Controlled aircirculation within the housing and particularly within the lower portionof the housing 12 mitigates the delta between ambient temperature andinternal temperature. Ports and baffles are located strategically withinthe Access Node 10 to force air flow where it is needed to carry heat upthe tube where the air is cooled. High thermal conductivity for theAccess Node components and a constant controlled air circulation, asindicated by the arrows 328 in FIG. 18, maintains only a smalldifference between internal and ambient temperature. In certainembodiments, the Access Node 10 provides approximately 1000 squareinches of cooling tube to dissipate heat and equalize temperature toambient. Heat is picked up by the moving air as it moves from the top 30of the Access Node 10 over the modules within the chassis 26. A baffledirects air through and behind the perforate wall 148 at 330. The airflow flows to both the front and rear of the perforate wall 148 at 332until it reaches the fan module 50 near the end 52 of the Access Node10. The heated air is directed along a path within the rear panel 28which provides dissipation to the ambient. The air is cooled by the timeit reaches the end 30 for a return trip. Cooling is provided withoutrequiring that the Access Node 10 bring in outside air.

The cooling tube is insulated from the front chassis using the Porongasket between the rear panel 28 and the chassis 26 so that solar andthermal heat loading on the housing has little impact on the coolingcapabilities. Mounting brackets that may be used to mount the housing tophysical structures such as beams or wall, which further dissipate heatfrom the rear panel 28. A fan control algorithm is provided to controlthe fan operation to maximize cooling using the emissivity of thematerial. A redundant fan system with alarm reporting is provided. Athermistor value is related to stored parameters which controls thespeed and therefore the volume of air depending on preprogrammed andstored algorithms.

Turning to FIG. 19, a vented plug 334 is provided in the Access Node 10at the latching arm assembly 24. The latching arm 24 is within aprotected recess on the bottom of the column shaped Access Node 10. Thevented plug provides an air inlet or outlet to the interior space 16 ofthe housing 12. This prevents pressure build up within the housing andallows air to be released and equalized.

In FIG. 20 is shown an alternative embodiment of the latch hook 336. Thelatch hook 336 has a block 338 that is mounted to the sliding strip 170by screws that extend through openings 340 and 342. The opening 340 isgenerally cylindrical and permits the latch hook 336 to pivot on thepin. The opening 342 is elongated, permitting limited pivoting of thelatch hook 336 about the opening 340. A set screw 344 functions as ajack screw to limit pivoting of the latch hook and to fine adjust andtighten the door in the closed position. Openings are provided at therear of the housing and through the perforate wall 148 to permittightening of the jack screw 344 with the door 14 in the closedposition.

A hook portion 346 extends from the block 338 to form a hook. The hookportion 346 is narrower, or thinner, than the block 338, resulting in astep 348 between the block 338 and the hook 346. A slot 350 is formed inthe end of the hook portion 346 and a bore 352 is formed through theclevis formed by the slot 350. A roller bearing 354 is inserted into theslot 350 and a pin 356 holds the roller bearing 354 in place.

Referring to FIG. 21, as shown in the left side of the figure, the latchhandle 24 at the bottom 52 of the housing 12 is in the open position.The latch handle 24 is attached to the sliding strip 170 that extendsalong an inside of the housing 12. As shows in the right side of thefigure, the sliding strip 170 has the slot 174 in which is attached thefastener 172 that permits the sliding strip 170 to move longitudinallyof the housing 12. The latch hook 336 is mounted on pins 358 on thesliding strip 170. The latch is open and the hook portion 346 has notyet entered a space 360 that is formed behind a front wall 362 of thepocket 58. The pocket 58 is attached by a fastener 364 to the door 14.

The door latch is partially closed in FIG. 22. In particular, the latchhandle 24 has been moved toward the latch position and is shownpartially there. The sliding strip 170 moves the latch hook 336 towardthe pocket 58 so that the roller bearing 354 rolls along an insidesurface of the front wall 362. Friction between the latch hook 336 andthe pocket 58 is reduced by the roller bearing 354, resulting in lessforce being required on the latch handle 24. Note that four latch hooks336 are being engaged into pockets 58 at the same time. The door 14 isforced against the housing 12 as the latch is engaged.

FIG. 23 shows the door latched fully engaged. The latch handle 24 is inthe fully latched position and is recessed within an opening in thebottom end 52 of the housing 12. The handle 24 is hidden from view andprotected from damage in this position. A lock, such as an electroniclock keeps the latch handle 24 in the closed position, as noted above.The latch hook 336 is fully engaged into the pocket 58. The hook portion346 is tapered to bear against the inside surface of the pocket wall 362in the fully latched position. The latching force is not borne by theroller bearing 354.

FIGS. 24A-24I shown the door 14 in the opened and closed positions.

Thus, there is shown and described a communication Access Node for callstations that includes a modular housing within which is mounted wireand wireless communication systems and power systems. The housing has achassis for mounting the electronics and battery modules and a backpanel for managing cables and providing heat dissipation. A door to thechassis is secured using latch hooks with roller bearings. Optical cabletermination is provided as a two sided patch panel. Dual power suppliesprovide power to internal components and to external components via adistribution module. Backup power is provided by a custom battery backupwith a charging controller. Cooling is controlled by dual fans and a fancontroller moving air through the housing using openings and baffles.Freestanding pedestal mounting of the Access Node is an option. Ventingthrough a plug prevents pressure build up.

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventors to embodywithin the patent warranted herein all changes and modifications asreasonably and properly come within the scope of their contribution tothe art.

I claim:
 1. An Access Node for a communication system, comprising: ahousing having: a chassis configured for mounting electronic modules;and a door mounted on the chassis by a hinge for movement between anopen position and a closed position; a plurality of pockets on the door;a sliding bar mounted in the chassis and operable to move in a slidingmotion between a first position and a second position; a plurality oflatch hooks mounted on the sliding bar; the latch hooks each including ahook portion shaped to engage into respective ones of the plurality ofpockets when the sliding bar is moved to the second position and thedoor is in the closed position; and a roller bearing mounted on the hookportion of each of the plurality of latch hooks.
 2. An Access Node asclaimed in claim 1, further comprising: an adjustable mounting betweenthe sliding bar and the latch hooks; and at least one set screw in eachof the latch hooks, the set screw being operable to secure theadjustable mounting in an adjusted position.
 3. An Access Node for acommunication system, comprising: a column shaped housing for enclosingelectronic and communication equipment for communication with aplurality of call stations; and a pedestal mount for mounting the columnshaped housing in a free-standing position on a floor or platform.
 4. AnAccess Node as claimed in claim 3, wherein the column shaped housingincludes a chassis and a rear panel, the pedestal mount being connectedto the rear panel.
 5. An Access Node for a communication system,comprising: a housing defining an interior space within which is mountedelectronics and communication equipment; a wall within the housing; apatch panel mounted on the perforate wall, the patch panel includingmodular patch panel members having cable terminators on both sides, themodular patch panel members being mounted perpendicular to the wall. 6.An Access Node as claimed in claim 5, further comprising: a plurality ofangle members attached to the wall, each of the angle members supportinga corresponding one of the modular patch panel members.
 7. An AccessNode for communicating with a plurality of call stations, comprising: arear panel including a mounting apparatus for mounting the Access Nodeto a mounting surface; a chassis having a shape for mounting on the rearpanel to form a wiring space between the rear panel and the chassis, thechassis including mounting brackets configured for mounting electronicsand communication modules in the chassis; a door movably connected tothe chassis, the door being movable into a closed position on thechassis to form an interior space of the Access Node, the door beingmovable to an open position to permit access to the interior space; anda plurality of modules mounted to the mounting brackets in the chassis,the plurality of modules being selected from the group of modulescomprising: an environmental sensor module, an auxiliary powerdistribution module, a cable patch panel, a first Ethernet switch orapplication server, a second Ethernet switch, a battery pack, anuninterruptable power supply module, a power supply module, a dual powersupply, a fan module, and a dual fan module.
 8. An Access Node asclaimed in claim 7, further comprising: a wireless access point modulemounted in the interior space of the access point.
 9. An Access Node asclaimed in claim 7, wherein the rear panel and the chassis and the doorare constructed so that no fasteners are accessible on an externalsurface of the Access Node when the chassis is mounted on the rear paneland the door is in the closed position.
 10. An Access Node forcommunicating with a plurality of call stations, comprising: a housingdefining an interior space; communication modules mounted within theinterior space; a power supply connected to external power to supplyelectrical power to the communication modules; a battery back-up modulemounted within the interior space and connected to supply electricalpower to the communication modules in the event of failure of theexternal power, the battery back-up module including a module chassisdefining a plurality of through openings, a plurality of battery cellswithin the plurality of through openings of the module chassis so thatterminals of the battery cells are exposed at opposite sides of themodule chassis, first and second printed circuit boards mounted on theopposite sides of the module chassis in electrical contact with thebattery cells; and a safety circuit connected to the first and secondprinted circuit boards of the battery back-up module, the safety circuitincluding a controller and at least one switch connected to thecontroller, the controller being operable to control charging anddischarging of the battery cells in the battery back-up module.
 11. Amethod for communicating with a plurality of call stations, comprising:enclosing a plurality of electronics and communications modules in anelongated housing to provide an Access Node; mounting the Access Node ata mounting location, the mounting including mounting a rear panel to amounting location; fastening a chassis to the rear panel; securing adoor in a closed position on the chassis to form an interior space;linking the Access Node to a plurality of call stations by communicationlinks; and receiving a communication from one of the call stations atthe Access Node.
 12. A method as claimed in claim 11, furthercomprising: cooling the electronics and communications modules bydirecting an air flow in a circulating path within the interior space,the circulating path passing air over the rear panel for dissipation ofheat through the rear panel.
 13. A method as claimed in claim 11,further comprising: securing the door in the closed position by latchhooks engaged into pockets, wherein the latch hooks roll over at least aportion of the pockets.
 14. A method as claimed in claim 11, furthercomprising: powering the electronics and communications modules by adual power supply; cooling the electronics and communications modules bydual fans; and powering the electronics and communications modules witha battery back-up on an event of failure of an external power source.15. A method as claimed in claim 11, further comprising: sealing therear mounting panel to the chassis; sealing the door to the chassis; andventing an interior space enclosed by the rear mounting panel and thechassis and the door.